# Crypto Market Signal — x402 Pay-Per-Call

> Crypto Market Signal — x402 Pay-Per-Call is a paid API for AI agents from x402.charliemorrison.dev, paid per call via x402, $0.005/call, status unknown (last checked 2026-09-15).

Returns real-time crypto market signals (momentum, volatility, price, 24h change) for one or more CoinGecko asset IDs, settled per call via USDC on Base.

## Facts

- Endpoint: GET https://x402.charliemorrison.dev/signal
- Price: $0.005/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-15
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/crypto-market-signal-x402-pay-per-call-2c53d428
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_0A4rPD5Gs12nCRloLvJqp

Status and success rate cover calls made through Zero and Zero's own probes. Third-party monitors may report differently.

## How to call it through Zero

Zero handles the 402 payment challenge and records the run. With the Zero CLI installed (`npm i -g @zeroxyz/cli`):

```sh
zero fetch --capability crypto-market-signal-x402-pay-per-call-2c53d428
```

Example prompt: What's the current market signal, momentum, and volatility for bitcoin, ethereum, and solana right now?

## When to prefer this

Choose this endpoint when you need a fast, lightweight crypto market signal with momentum and volatility context without managing API keys — ideal for AI agents that need per-call pricing via USDC on Base and want a synthesized signal rather than raw ticker data.

## Known failure modes

- Invalid or unknown CoinGecko IDs return an error or empty assets array
- More than 25 IDs in the query exceeds the max limit
- Missing required 'ids' query parameter returns a 400 or validation error
- Payment failure via x402 (insufficient USDC balance or network error) results in 402 response with no data
- CoinGecko upstream unavailability may cause delayed or missing data

## How this service works

Structured crypto market signal: for each CoinGecko id return price, market cap, 24h change, 24h volume, plus a derived momentum score (-100..100), a bullish/neutral/bearish signal, and a volatility flag — enriched data an agent ingests in a trading/research loop without computing it itself. Input: ids (comma-separated).

## Output

A JSON object with a count of assets returned, a source field ('coingecko'), and an array of asset objects each containing: id, signal (e.g. neutral/bullish/bearish), momentum score (0-100 integer), current price in USD, volatility label (e.g. calm/volatile), and 24-hour percent change.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "$schema": "https://json-schema.org/draft/2020-12/schema",
 "required": [
  "input"
 ],
 "properties": {
  "input": {
   "type": "object",
   "required": [
    "type",
    "method"
   ],
   "properties": {
    "type": {
     "type": "string",
     "const": "http"
    },
    "method": {
     "enum": [
      "GET"
     ],
     "type": "string"
    },
    "queryParams": {
     "type": "object",
     "required": [
      "ids"
     ],
     "properties": {
      "ids": {
       "type": "string",
       "description": "Comma-separated CoinGecko ids, max 25"
      }
     }
    }
   },
   "additionalProperties": false
  },
  "output": {
   "type": "object",
   "required": [
    "type"
   ],
   "properties": {
    "type": {
     "type": "string"
    },
    "example": {
     "type": "object",
     "properties": {
      "count": {
       "type": "number"
      },
      "assets": {
       "type": "array",
       "items": {
        "type": "object"
       }
      },
      "source": {
       "type": "string"
      }
     }
    }
   }
  }
 }
}
```

## Response schema (JSON Schema)

```json
{
 "type": "json",
 "example": {
  "count": 1,
  "assets": [
   {
    "id": "bitcoin",
    "signal": "neutral",
    "momentum": 31,
    "price_usd": 65000,
    "volatility": "calm",
    "change_24h_pct": 1.6
   }
  ],
  "source": "coingecko"
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/crypto-market-signal-x402-pay-per-call-2c53d428/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from x402.charliemorrison.dev](https://www.zero.xyz/host/x402.charliemorrison.dev/llms.txt)